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1.
Protein Pept Lett ; 27(1): 48-59, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31362651

RESUMO

BACKGROUND: Channa striata are speculated to contain bioactive proteins with the ability to enhancing wound healing. It is commonly consumed after surgery for a faster recovery of the wound. OBJECTIVE: To identify the bioactive proteins and evaluate their ability in cell proliferation and angiogenesis promotion. MATERIAL AND METHODS: Freeze-Dried Water Extracts (FDWE) and Spray-Dried Water Extracts (SDWE) of C. striata were tested with MTT assay using EA.hy926 endothelial cell line and ex-vivo aortic ring assay. Later the proteins were fractionated and analysed using an LC-QTOF mass spectrometer. The data generated were matched with human gene database for protein similarity and pathway identification. RESULTS: Both samples have shown positive cell proliferation and pro-angiogenic activity. Four essential proteins/genes were identified, which are collagen type XI, actin 1, myosin light chain and myosin heavy chain. The pathways discovered that related to these proteins are integrin pathway, Slit-Robo signalling pathway and immune response C-C Chemokine Receptor-3 signalling pathway in eosinophils, which contribute towards wound healing mechanism. CONCLUSIONS: The results presented have demonstrated that C. striata FDWE and SDWE protein fractions contain bioactive proteins that are highly similar to human proteins and thus could be involved in the wound healing process via specific biological pathways.


Assuntos
Proliferação de Células/efeitos dos fármacos , Misturas Complexas/química , Venenos de Peixe/química , Proteínas/química , Cicatrização/efeitos dos fármacos , Actinas/química , Animais , Aorta/metabolismo , Colágeno/química , Misturas Complexas/metabolismo , Células Endoteliais/metabolismo , Venenos de Peixe/metabolismo , Peixes , Humanos , Integrinas/metabolismo , Masculino , Miosinas/química , Proteínas/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores CCR3/metabolismo , Transdução de Sinais , Espectrometria de Massas em Tandem
2.
J Proteomics ; 201: 12-26, 2019 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-30953730

RESUMO

The Estuarine stonefish (Synanceia horrida) is recognised as one of the most venomous fish species in the world but the overall venom composition has yet to be investigated using in-depth transcriptomic and proteomic methods. To date, known venom components are restricted to a hyaluronidase and a large, pore-forming toxin known as Stonustoxin (SNTX). Transcriptomic sequencing of the venom gland resulted in over 170,000 contigs with only 0.4% that were homologous to putative venom proteins. Integration of the transcriptomic data with proteomic data from the S. horrida venom confirmed the hyaluronidase and SNTX to be present, together with several other protein families including major contributions from C-type lectins. Other protein families observed included peroxiredoxin and several minor protein families such as Golgi-associated plant pathogenesis related proteins, tissue pathway factor inhibitors, and Kazal-type serine protease inhibitors that, although not putative venom proteins, may contribute to the venom's adverse effects. BIOLOGICAL SIGNIFICANCE: Proteomic analysis of milked Synanceia horrida venom, paired with transcriptomic analysis of the venom gland tissue revealed for the first time the composition of one of the world's most dangerous fish venoms. The results demonstrate that the venom is relatively less complex compared to other well-studied venomous animals with a number of unique proteins not previously found in animal venoms.


Assuntos
Glândulas Exócrinas/metabolismo , Proteínas de Peixes/metabolismo , Venenos de Peixe/metabolismo , Perciformes/metabolismo , Proteômica , Animais
3.
J Proteomics ; 187: 200-211, 2018 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-30098406

RESUMO

The biological activities observed upon envenomation by Scorpaena plumieri could be linked to both the venom and the skin mucus. Through a proteomic/functional approach we analyzed protein composition and biological activities of the venom and skin mucus. We identified 885 proteins: 722 in the Venomous Apparatus extracts (Sp-VAe) and 391 in the Skin Mucus extract (Sp-SMe), with 494 found exclusively in Sp-VAe, being named S. plumieri Venom Proteins (Sp-VP), while 228 were found in both extracts. The majority of the many proteins identified were not directly related to the biological activities reported here. Nevertheless, some were classified as toxins/potentially interesting molecules: lectins, proteases and protease inhibitors were detected in both extracts, while the pore-forming toxin and hyaluronidase were associated with Sp-VP. Proteolytic and anti-microbial activities were linked to both extracts, while the main toxic activities - cardiovascular, inflammatory, hemolytic and nociceptive - were elicited only by Sp-VAe. Our study provided a clear picture on the composition of the skin mucus and the venom. We also show that the classic effects observed upon envenomation are produced by molecules from the venomous gland. Our results add to the growing catalogue of scorpaeniform fish venoms and their skin mucus proteins. SIGNIFICANCE: In this study a large number of proteins - including classical and non-classical toxins - were identified in the venomous apparatus and the skin mucus extracts of the Scorpaena plumieri fish through shotgun proteomic approach. It was shown that the toxic effects observed upon envenomation are elicited by molecules originated from the venomous gland. These results add to the growing catalogue of scorpaeniform fish venoms and their skin mucus proteins - so scarcely explored when compared to the venoms and bioactive components of terrestrial animals. Data are available via ProteomeXchange with identifier PXD009983.


Assuntos
Proteínas de Peixes/análise , Proteínas de Peixes/fisiologia , Venenos de Peixe/análise , Muco/química , Perciformes/metabolismo , Proteômica/métodos , Pele/química , Animais , Proteínas de Peixes/metabolismo , Venenos de Peixe/metabolismo , Venenos de Peixe/fisiologia , Masculino , Camundongos , Muco/metabolismo , Ratos , Ratos Wistar , Pele/metabolismo , Extratos de Tecidos/análise , Extratos de Tecidos/metabolismo
4.
J Chem Inf Model ; 57(4): 929-941, 2017 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-28301157

RESUMO

Antimicrobial peptides (AMPs) are part of the innate host defense system, and they are produced by living organisms to defend themselves against infections. Pardaxin is a cationic AMP with antimicrobial and antitumor activities that has potential to be used as a novel antibiotic or for drug delivery in cancer therapy. This peptide acts on the membrane of target cells and can lead to lysis using different mechanisms of action. Here, we conducted 4.5 µs all-atom molecular dynamics (MD) simulations to determine the critical fragments and residues of Pardaxin for early insertion into different lipid bilayers. Our results revealed that the N-terminal domain of the peptide, particularly the Phe 2 and (/or) Phe 3 residues, has a crucial role in early insertion, independent of the type of lipid bilayers.


Assuntos
Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/metabolismo , Venenos de Peixe/química , Venenos de Peixe/metabolismo , Bicamadas Lipídicas/metabolismo , Simulação de Dinâmica Molecular , Fosfolipídeos/metabolismo , Difusão , Conformação Proteica
5.
Toxins (Basel) ; 9(2)2017 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-28212333

RESUMO

Fish venoms are often poorly studied, in part due to the difficulty in obtaining, extracting, and storing them. In this study, we characterize the cardiovascular and neurotoxic effects of the venoms from the following six species of fish: the cartilaginous stingrays Neotrygon kuhlii and Himantura toshi, and the bony fish Platycephalus fucus, Girella tricuspidata, Mugil cephalus, and Dentex tumifrons. All venoms (10-100 µg/kg, i.v.), except G. tricuspidata and P. fuscus, induced a biphasic response on mean arterial pressure (MAP) in the anesthetised rat. P. fucus venom exhibited a hypotensive response, while venom from G. tricuspidata displayed a single depressor response. All venoms induced cardiovascular collapse at 200 µg/kg, i.v. The in vitro neurotoxic effects of venom were examined using the chick biventer cervicis nerve-muscle (CBCNM) preparation. N. kuhlii, H. toshi, and P. fucus venoms caused concentration-dependent inhibition of indirect twitches in the CBCNM preparation. These three venoms also inhibited responses to exogenous acetylcholine (ACh) and carbachol (CCh), but not potassium chloride (KCl), indicating a post-synaptic mode of action. Venom from G. tricuspidata, M. cephalus, and D. tumifrons had no significant effect on indirect twitches or agonist responses in the CBCNM. Our results demonstrate that envenoming by these species of fish may result in moderate cardiovascular and/or neurotoxic effects. Future studies aimed at identifying the molecules responsible for these effects could uncover potentially novel lead compounds for future pharmaceuticals, in addition to generating new knowledge about the evolutionary relationships between venomous animals.


Assuntos
Doenças Cardiovasculares/induzido quimicamente , Sistema Cardiovascular/efeitos dos fármacos , Venenos de Peixe/toxicidade , Peixes Venenosos/metabolismo , Junção Neuromuscular/efeitos dos fármacos , Síndromes Neurotóxicas/etiologia , Animais , Pressão Arterial/efeitos dos fármacos , Doenças Cardiovasculares/fisiopatologia , Sistema Cardiovascular/fisiopatologia , Galinhas , Relação Dose-Resposta a Droga , Venenos de Peixe/metabolismo , Peixes Venenosos/classificação , Contração Muscular/efeitos dos fármacos , Junção Neuromuscular/fisiopatologia , Síndromes Neurotóxicas/fisiopatologia , Ratos , Fatores de Tempo
6.
Toxicon ; 125: 19-23, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27867093

RESUMO

BACKGROUND: The potential costs of venom production may be significant to many marine venomous taxa. In general, the parameters that influence the rate of venom production are poorly understood, but seem to be related to feeding frequency. METHODS: This study examines the effects of starvation on venom profile and venom yield on the estuarine stonefish (Synanceia horrida). In total, the venom of eight stonefishes was tested under two feeding regimes. Over a four week period, one of the two groups underwent an episode of suspended feeding, while the other was fed on a daily basis. The effect of time on venom replacement was determined by a paired T-test. ANOVA was performed to analyze differences in venom weight between fed and unfed treatments. RESULTS: Nutritional suspension was found to have a significant effect on the quantity of venom produced. SDS-PAGE gel and FPLC revealed that the components of the venom collected from both groups were similar, indicating that four weeks is an adequate time to regenerate key venom components but not replenish initial venom quantities. CONCLUSIONS: Venom production was found to be affected by starvation.


Assuntos
Comportamento Alimentar , Venenos de Peixe/metabolismo , Peixes Venenosos/fisiologia , Perciformes/fisiologia , Animais , Dieta , Peixes Venenosos/metabolismo , Perciformes/metabolismo , Inanição/metabolismo , Fatores de Tempo
7.
Sci Rep ; 6: 21935, 2016 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-26916342

RESUMO

Stingrays commonly cause human envenoming related accidents in populations of the sea, near rivers and lakes. Transcriptomic profiles have been used to elucidate components of animal venom, since they are capable of providing molecular information on the biology of the animal and could have biomedical applications. In this study, we elucidated the transcriptomic profile of the venom glands from two different freshwater stingray species that are endemic to the Paraná-Paraguay basin in Brazil, Potamotrygon amandae and Potamotrygon falkneri. Using RNA-Seq, we identified species-specific transcripts and overlapping proteins in the venom gland of both species. Among the transcripts related with envenoming, high abundance of hyaluronidases was observed in both species. In addition, we built three-dimensional homology models based on several venom transcripts identified. Our study represents a significant improvement in the information about the venoms employed by these two species and their molecular characteristics. Moreover, the information generated by our group helps in a better understanding of the biology of freshwater cartilaginous fishes and offers clues for the development of clinical treatments for stingray envenoming in Brazil and around the world. Finally, our results might have biomedical implications in developing treatments for complex diseases.


Assuntos
Glândulas Exócrinas/metabolismo , Proteínas de Peixes/genética , Venenos de Peixe/metabolismo , Rajidae/metabolismo , Animais , Brasil , Água Doce , Perfilação da Expressão Gênica , Hialuronoglucosaminidase/genética , Rajidae/genética , Especificidade da Espécie
8.
PLoS One ; 9(5): e97664, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24825326

RESUMO

Examination of genetic data (mitochondrial cytochrome c oxidase I) for western Atlantic clingfishes revealed two distinct lineages within a group of individuals originally identified as Acyrtus artius. Subsequent investigation of preserved voucher specimens was conducted to reconcile the genetic data and the existing classification, which is based on morphology. In addition to discovering that one of the genetic lineages is an undescribed species, which we describe as Acyrtus lanthanum, new species, we found that the nominal species Acyrtus artius has a putative venom gland associated with the subopercle that has been overlooked since the species was described nearly 60 years ago. The new species lacks the subopercular gland as does Acyrtus rubiginosus, but one is present in the related Arcos nudus. Venom glands have not been reported previously for the Gobiesocidae, and the venom gland described herein for Acyrtus and Arcos represents the first example in teleost fishes of a venom gland associated with the subopercle.


Assuntos
Glândulas Exócrinas/anatomia & histologia , Variação Genética/genética , Perciformes/classificação , Perciformes/genética , Filogenia , Animais , Oceano Atlântico , Sequência de Bases , Região do Caribe , Glândulas Exócrinas/metabolismo , Venenos de Peixe/metabolismo , Dados de Sequência Molecular , Perciformes/anatomia & histologia , Análise de Sequência de DNA , Especificidade da Espécie , Terminologia como Assunto
9.
J Microbiol Biotechnol ; 24(7): 905-13, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24690634

RESUMO

Lj-RGD3, an RGD (Arg-Gly-Asp) toxin protein from the salivary gland of Lampetra japonica, exhibits antifungal activity against Candida albicans. Lj-RGD3 has three RGD motifs and shows homology to histidine-rich glycoprotein. We synthesised two mutant derivatives of Lj-RGD3: Lj-26, which lacks all three RGD motifs and contains no His residues; and Lj-112, which lacks only the three RGD motifs. We investigated the effects of the wild-type and mutated toxins on a gram-positive bacterium (Escherichia coli), a gram-negative bacterium (Staphylococcus aureus), and a fungus (C. albicans). rLj-RGD3 and its mutants exhibited antifungal but not antibacterial activity, as measured by a radial diffusion assay. The C. albicans inhibition zone induced by rLj-112 was larger than that induced by the other proteins, and its inhibitory effect on C. albicans was dose-dependent. In viable-count assays, the rLj-112 MIC was 7.7 micrometer, whereas the MIC of the positive control (ketoconazole) was 15 micrometer. Time-kill kinetics demonstrated that rLj-112 effectively killed C. albicans at 1× and 2× MIC within 12 and 6 h, respectively. Electron microscopy analysis showed that rLj-RGD3 and rLj-112 induced C. albicans lysis. Our results demonstrate a novel anticandidal activity for rLj-RGD3 and its mutant derivatives.


Assuntos
Antifúngicos/química , Antifúngicos/farmacologia , Venenos de Peixe/química , Venenos de Peixe/farmacologia , Oligopeptídeos/química , Oligopeptídeos/farmacologia , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacologia , Sequência de Aminoácidos , Antifúngicos/metabolismo , Bactérias/efeitos dos fármacos , Sequência de Bases , Candida/efeitos dos fármacos , Venenos de Peixe/genética , Venenos de Peixe/metabolismo , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Mutação/genética , Oligopeptídeos/genética , Oligopeptídeos/metabolismo , Conformação Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência
10.
Int Immunopharmacol ; 14(4): 513-22, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22940186

RESUMO

Recently our group described that Nattectin, a C-type lectin of the venom of Thalassophryne nattereri shows a potent pro-inflammatory capacity. Here, we demonstrated that Nattectin is able to induce M1 macrophage marker iNOS, and up-regulate the expression of MHC class II, CD80, CD86 and CD40 molecules. The increase in MHC class II and CD49a integrin expression with MMP-9 production and endocytic capacity depend on lectin function of Nattectin. Moreover, the polarization of peritoneal and bone marrow-derived macrophages induced by Nattectin to M1 profile is dependent on Th1 cytokines (IL-12 and IFN-γ), and negatively regulated by Th2 cytokines (IL-4, IL-10 and IL-13). Also we reveal that IL-4 play a dual role in this polarization: a regular action of IL-4 was seen in the negative regulation of the CD40 expression, but an unexpected positive regulation was seen in the expression of CCR7 and MHC class II. Finally, our in vivo studies showed that the influx of neutrophils and small peritoneal macrophage--F4/80(low)MHCII(hi) induced by Nattectin is totally dependent on IL-4 and IFN-γ cytokines. Furthermore, the induction of IL-6 release is negatively regulated by IL-4 and positively regulated by IL-12 and IFN-γ. Together, the results allowed us to expand the knowledge about the regulation of macrophage activation, as well as confirmed the ability of Nattectin, a fish C-type lectin, as an important immunomodulatory agent.


Assuntos
Batracoidiformes/fisiologia , Venenos de Peixe/química , Interferon gama/metabolismo , Interleucina-4/metabolismo , Lectinas Tipo C/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Animais , Células da Medula Óssea/efeitos dos fármacos , Feminino , Venenos de Peixe/metabolismo , Interferon gama/genética , Interleucina-10/genética , Interleucina-10/metabolismo , Interleucina-13/genética , Interleucina-13/metabolismo , Interleucina-4/genética , Lectinas Tipo C/química , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL
11.
Biochimie ; 93(6): 971-80, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21396978

RESUMO

Lectins are glycan-binding receptors that recognize glycan epitopes on foreign pathogens and in the host systems. They can be involved in functions that include innate immunity, development, immune regulation and homeostasis. Several lectins have been purified and characterized from fish species. In this work, using cation-exchange chromatography, a galactose-specific lectin belonging to the family of C-type lectins was isolated from the venom of the Brazilian venomous fish Thalassophryne nattereri. Nattectin is a basic, non-glycosilated, 15 kDa monomeric protein. It exhibits hemagglutination activity that is independent of Ca(2+). We also demonstrated a lectin activity for Nattectin in the innate immune system, especially in neutrophil mobilization in mice, indicating that marine organisms are source of immunomodulator agents.


Assuntos
Batracoidiformes , Venenos de Peixe/metabolismo , Fatores Imunológicos/metabolismo , Lectinas Tipo C/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Sítios de Ligação , Cálcio/metabolismo , Movimento Celular , Sequência Conservada , Venenos de Peixe/administração & dosagem , Venenos de Peixe/química , Venenos de Peixe/isolamento & purificação , Galactose/metabolismo , Testes de Hemaglutinação , Membro Posterior/patologia , Humanos , Imunidade Inata , Fatores Imunológicos/administração & dosagem , Fatores Imunológicos/química , Fatores Imunológicos/isolamento & purificação , Inflamação/induzido quimicamente , Inflamação/imunologia , Lectinas Tipo C/administração & dosagem , Lectinas Tipo C/química , Lectinas Tipo C/isolamento & purificação , Leucócitos/efeitos dos fármacos , Leucócitos/fisiologia , Metaloproteinases da Matriz/metabolismo , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Estrutura Terciária de Proteína , Análise de Sequência de Proteína , Homologia Estrutural de Proteína
12.
Biophys J ; 98(4): 576-85, 2010 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-20159154

RESUMO

Pardaxin is a 33-amino-acid neurotoxin from the Red Sea Moses sole Pardachirus marmoratus, whose mode of action shows remarkable sensitivity to lipid chain length and charge, although the effect of pH is unclear. Here we combine optical spectroscopy and dye release experiments with laser scanning confocal microscopy and natural abundance (13)C solid-state nuclear magnetic resonance to provide a more complete picture of how pardaxin interacts with lipids. The kinetics and efficiency of release of entrapped calcein is highly sensitive to pH. In vesicles containing zwitterionic lipids (PC), release occurs most rapidly at low pH, whereas in vesicles containing 20% anionic lipid (PG), release occurs most rapidly at high pH. Pardaxin forms stable or transient pores in PC vesicles that allow release of contents without loss of vesicle integrity, whereas the inclusion of PG promotes total vesicle collapse. In agreement with this, solid-state nuclear magnetic resonance reveals that pardaxin takes up a trans-membrane orientation in 14-O-PC/6-O-PC bicelles, whereas the inclusion of 14-0-PG restricts it to contacts with lipid headgroups, promoting membrane lysis. Pore formation in zwitterionic vesicles is more efficient than lysis of anionic vesicles, suggesting that electrostatic interactions may trap pardaxin in several suboptimal interconverting conformations on the membrane surface.


Assuntos
Venenos de Peixe/metabolismo , Lipossomas Unilamelares/química , Lipossomas Unilamelares/metabolismo , Sequência de Aminoácidos , Venenos de Peixe/química , Fluoresceínas/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Metabolismo dos Lipídeos , Lipídeos/química , Espectroscopia de Ressonância Magnética , Microscopia Confocal , Dados de Sequência Molecular , Permeabilidade , Porosidade , Conformação Proteica , Prótons
13.
Toxicon ; 55(6): 1188-94, 2010 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-20080118

RESUMO

Rays are common elasmobranches in the northern waters of Persian Gulf and Oman Sea that may have one or more mineralized serrated stingers on the whip-like tail. The stingers are covered by epidermal cells among which some can produce venom. When these animals are dorsally touched, the stinger can be introduced into the aggressor by a whip reflex mechanism of the tail when the pectoral fins are touched, causing severe mechanical injuries and inoculating the venom. The exact localization of the venom secretory cells in the stinger of different species is controversial, but it is known that the cells are preferentially located in the ventro-lateral grooves in marine stingrays. A comparative morphological characterization of the stinger epidermal tissue of different ray species in the northern part of Persian Gulf and Oman Sea was carried out in this study. EDTA was used for decalcification of stings and conventional histological processes were subsequently employed. The results indicated that structure of dermis and epidermis layers of stings in all species are similar to the structure of corresponding layers in other parts of fish's body. The results of the present study have shown that all examined species of Dasyatidae family, but not Myliobatidae and Gymnuridae families, had venom secretory cells. Distribution of venom secretory cells varies in each species and is often located around or inside the stinger ventro-lateral grooves. These differences among the stingers of various species may explain the envenomation severity in these species.


Assuntos
Células Epidérmicas , Glândulas Exócrinas/anatomia & histologia , Venenos de Peixe/metabolismo , Peixes Venenosos/fisiologia , Rajidae/fisiologia , Animais , Mordeduras e Picadas , Epiderme/metabolismo , Glândulas Exócrinas/metabolismo , Oriente Médio , Água do Mar
14.
J Biol Chem ; 285(6): 3883-3895, 2010 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-19959835

RESUMO

Lipopolysaccharide (LPS), the major constituent of the outer membrane of Gram-negative bacteria, is an important element against permeability of bactericidal agents, including antimicrobial peptides. However, structural determinants of antimicrobial peptides for LPS recognition are not clearly understood. Pardaxins (Pa1, Pa2, Pa3, and Pa4) are a group of pore-forming bactericidal peptides found in the mucous glands of sole fishes. Despite having a low net positive charge, pardaxins contain a broad spectrum of antibacterial activities. To elucidate the structural basis of LPS interactions of pardaxins, herein, we report the first three-dimensional structure of Pa4 bound to LPS micelles. The binding kinetics of Pa4 with LPS is estimated using [(15)N-Leu-19] relaxation dispersion NMR experiments. LPS/Pa4 interactions are further characterized by a number of biophysical methods, including isothermal titration calorimetry, (31)P NMR, saturation transfer difference NMR, dynamic light scattering, and IR spectroscopy. In the LPS-Pa4 complex, Pa4 adopts a unique helix-turn-helix conformation resembling a "horseshoe." Interestingly, the LPS-bound structure of Pa4 shows striking differences with the structures determined in lipid micelles or organic solvents. Saturation transfer difference NMR identifies residues of Pa4 that are intimately associated with LPS micelles. Collectively, our results provide mechanistic insights into the outer membrane permeabilization by pardaxin.


Assuntos
Anti-Infecciosos/química , Venenos de Peixe/química , Lipopolissacarídeos/química , Espectroscopia de Ressonância Magnética/métodos , Animais , Anti-Infecciosos/metabolismo , Membrana Celular/química , Membrana Celular/metabolismo , Permeabilidade da Membrana Celular , Dicroísmo Circular , Escherichia coli/metabolismo , Proteínas de Peixes/química , Proteínas de Peixes/metabolismo , Venenos de Peixe/metabolismo , Concentração de Íons de Hidrogênio , Lipopolissacarídeos/metabolismo , Micelas , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termodinâmica
15.
Peptides ; 30(12): 2191-9, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19682520

RESUMO

Brazilian freshwater stingrays, Potamotrygon gr. orbigyni, are relatively common in the middle-western regions of Brazil, where they are considered an important public health threat. In order to identify some of their naturally occurring toxin peptides available in very low amounts, we combine analytical protocols such as reversed-phase high-performance liquid chromatography (RP-HPLC), followed by a biological microcirculatory screening and mass spectrometry analysis. Using this approach, one bioactive peptide was identified and characterized, and two analogues were synthesized. The natural peptide named Porflan has the primary structure ESIVRPPPVEAKVEETPE (MW 2006.09 Da) and has no similarity with any bioactive peptide or protein found in public data banks. Bioassay protocols characterized peptides as presenting potent activity in a microcirculatory environment. The primary sequences and bioassay results, including interactions with the membrane phospholipids, suggest that these toxins are a new class of fish toxins, directly involved in the inflammatory processes of a stingray sting.


Assuntos
Venenos de Peixe/metabolismo , Peptídeos/química , Peptídeos/metabolismo , Rajidae/metabolismo , Sequência de Aminoácidos , Animais , Cromatografia Líquida de Alta Pressão , Venenos de Peixe/química , Espectrometria de Massas , Simulação de Dinâmica Molecular , Dados de Sequência Molecular , Espectrometria de Massas em Tandem
16.
J Exp Zool A Ecol Genet Physiol ; 307(9): 488-99, 2007 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-17620305

RESUMO

Mammals envenomed by either the Eastern diamondback rattlesnake (Crotalus adamanteus) or the cottonmouth (Agkistrodon piscivorus piscivorus) exhibit an immediate but transitory pupillar contraction, a parasympathomimetic effect mediated through the ciliary ganglion that can be prevented by a retrobulbar injection of anesthetic. The venom of the cottonmouth injected into the lymph spaces of the frog (Rana pipiens) produces an immediate and total collapse of the lung sacs. Applied locally to the surface, it produces a constriction that eventually collapses the entire sac. Tests of venoms and toxins from both anterior and posterior parts of the venom apparatus indicate that the lung-collapsing moiety originates in the accessory, not the main portion of the venom gland. This is the first example of a functional specialization within the whole structure. It seems that this factor is elaborated primarily in snakes that prey upon frogs, although insufficient data are available from this study to confirm this. In both reptile species, the predatory strike is accompanied by an immediate effect, perhaps mediated by the parasympathetic nervous system, designed to incapacitate the prey and facilitate capture. These effects cannot now be attributed to neurotoxins because the effect of the former is transitory (and not lethal) and neither has been purified sufficiently to determine potency or structure. Both take part in securing, but not killing, the prey, and both directly oppose the sympathetic nervous system "fright-fight/flight" response. Evidence is presented to support the possibility that known epigenetic mechanisms are capable of effecting heritable changes in gene expression that could allow for the development of factors that facilitate prey acquisition and promote rapid adaptation to environmental change.


Assuntos
Venenos de Peixe/farmacologia , Venenos de Moluscos/farmacologia , Comportamento Predatório/fisiologia , Venenos de Serpentes/farmacologia , Adaptação Biológica/genética , Adaptação Biológica/fisiologia , Agkistrodon , Animais , Bothrops , Gatos , Crotalus , Epigênese Genética , Reação de Fuga , Venenos de Peixe/genética , Venenos de Peixe/metabolismo , Peixes Venenosos , Pulmão/efeitos dos fármacos , Venenos de Moluscos/genética , Venenos de Moluscos/metabolismo , Fatores de Crescimento Neural/efeitos dos fármacos , Octopodiformes , Sistema Nervoso Parassimpático/efeitos dos fármacos , Pupila/efeitos dos fármacos , Coelhos , Rana pipiens , Venenos de Serpentes/genética , Venenos de Serpentes/metabolismo , Viperidae
17.
Toxicon ; 50(5): 688-97, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17659760

RESUMO

Marine and freshwater stingrays are characterized by the presence of one to three mineralized serrated stingers on the tail, which are covered by epidermal cells secreting venom. When these animals are dorsally touched, the stinger can be introduced into the aggressor by a whip reflex mechanism of the tail, causing severe mechanical injuries and inoculating the venom. Accidents in humans are frequent causing intense local pain, oedema and erythema. Bacterial secondary infection is also common. In addition, injuries involving freshwater stingrays frequently cause a persistent cutaneous necrosis. The exact localization of the venom secretory epidermal cells in the stinger is controversial, but it is known that it is preferentially located in the ventrolateral grooves. A comparative morphological analysis of the stinger epidermal tissue of different marine and freshwater Brazilian stingray species was carried out. The results indicate that in freshwater species there is a larger number of protein secretory cells, of two different types, spread over the whole stinger epidermis, while in marine species the protein secretory cells are located only around or inside the stinger ventrolateral grooves. These differences between the stingers of the two groups can justify the more severe envenomation accidents with the freshwater species when compared with the marine species.


Assuntos
Mordeduras e Picadas , Células Epidérmicas , Venenos de Peixe/metabolismo , Peixes Venenosos , Rajidae/anatomia & histologia , Animais , Brasil , Epiderme/metabolismo , Epiderme/ultraestrutura , Glândulas Exócrinas/anatomia & histologia , Glândulas Exócrinas/metabolismo , Água Doce , Água do Mar , Rajidae/fisiologia , Especificidade da Espécie
18.
Toxicon ; 47(5): 575-83, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16564065

RESUMO

Stingrays of the family Potamotrygonidae are widespread throughout river systems of South America that drain into the Atlantic Ocean. Some species are endemic to the most extreme freshwater environment of the Brazil and cause frequent accidents to humans. The envenomation causes immediate, local, and intense pain, soft tissue edema, and a variable extent of bleeding. The present study was carried out in order to describe the principal biological and some biochemical properties of the Brazilian Potamotrygon fish venoms (Potamotrygon cf. scobina and P. gr. orbignyi). Both stingray venoms induced significant edematogenic and nociceptive responses in mice. Edematogenic and nociceptive responses were reduced when the venom was incubated at 37 or 56 degrees C. The results showed striking augments of leukocytes rolling and adherent cells to the endothelium of cremaster mice induced by both venoms. The data also presented that injection of both venoms induced necrosis, low level of proteolytic activity, without inducing haemorrhage. But when the venoms of both stingray species were injected together with their mucus secretion, the necrotizing activity was more vigorous. The present study provided in vivo evidence of toxic effects for P. cf. scobina and P. gr. orbignyi venoms.


Assuntos
Venenos de Peixe/toxicidade , Rajidae/metabolismo , Animais , Brasil , Relação Dose-Resposta a Droga , Edema/induzido quimicamente , Venenos de Peixe/metabolismo , Hemorragia/induzido quimicamente , Inflamação/induzido quimicamente , Masculino , Camundongos , Necrose/induzido quimicamente , Dor/induzido quimicamente , Temperatura , Fatores de Tempo
19.
Toxicon ; 45(5): 595-601, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15777955

RESUMO

Soapfishes contain peptide toxins (grammistins) in the skin secretion. Two grammistins (Gs 1 and Gs 2) and six grammistins (Pp 1, Pp 2a, Pp 2b, Pp 3, Pp 4a and Pp 4b) have already been isolated from Grammistes sexlineatus and Pogonoperca punctata, respectively. In this study, five grammistins (Gs A-E), together with grammistins Gs 1 and Gs 2, were further isolated from G. sexlineatus by gel filtration and reverse-phase HPLC. Sequence analyses revealed that grammistins Gs A (28 residues) and Gs C (26 residues) are analogous to grammistin Pp 3 and grammistin Gs B (12 residues) to grammistin Pp 1, while grammistins Gs D (13 residues) and Gs E (13 residues) are identical with grammistins Pp 1 and Pp 2b, respectively. Grammistins Gs A-C exhibited antibacterial activity with a broad spectrum against nine species of bacteria in common with the other grammistins but had no hemolytic activity differing from the other grammistins. Grammistins Gs A-E, Gs 1 and Gs 2 could release carboxyfluorescein entrapped within liposomes made of either phosphatidylcholine or phosphatidylglycerol/phosphatidylcholine (3:1), demonstrating their membrane-lytic activity. However, no clear relationship between the membrane-lytic activity and the biological activity of grammistins was recognized.


Assuntos
Antibacterianos/toxicidade , Venenos de Peixe/genética , Venenos de Peixe/toxicidade , Perciformes/metabolismo , Pele/metabolismo , Sequência de Aminoácidos , Animais , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Venenos de Peixe/metabolismo , Fluoresceínas/metabolismo , Bactérias Gram-Positivas/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Lipossomos/metabolismo , Dados de Sequência Molecular , Perciformes/genética , Análise de Sequência de Proteína
20.
Toxicon ; 45(2): 155-61, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15626364

RESUMO

The accidents caused by Thalassophryne maculosa fish venoms are frequent and represent a public health problem in some regions of Venezuela. Most accidents occur in the fishing communities and tourists. The clinical picture is characterized by severe pain, dizziness, fever, edema, and necrosis. Due to the lack of efficient therapy it may take weeks, or even months for complete recovery of the victims. The investigations presented here were undertaken to assess the eletrophoretical profile and principal biological properties of the T. maculosa venom. Venom obtained from fresh captured specimens of this fish was tested in vitro or in animal models for a better characterization of its toxic activities. In contrast to other fish venoms, T. maculosa venom showed relative low LD50. The injection of venom in the footpad of mice reproduced a local inflammatory lesion similar to that described in humans. Significant increase of the nociceptive and edematogenic responses was observed followed within 48 h by necrosis. Pronounced alterations on microvascular hemodynamics were visualized after venom application. These alterations were represented by fibrin depots and thrombus formation followed by complete venular stasis and transient arteriolar contraction. T. maculosa venom is devoid of phospholipase A2 activity, but the venom showed proteolytic and myotoxic activities. SDS-Page analysis of the crude venom showed important bands: one band located above 97 M(w), one band between 68 and 97 M(w), one major band between 29 and 43 M(w) and the last one located below 18.4 M(w) Then, the results presented here support that T. maculosa venom present a mixture of bioactive toxins involved in a local inflammatory lesion.


Assuntos
Venenos de Peixe/toxicidade , Animais , Batracoidiformes , Caseínas/metabolismo , Relação Dose-Resposta a Droga , Edema/induzido quimicamente , Venenos de Peixe/química , Venenos de Peixe/metabolismo , Hemorragia/induzido quimicamente , Temperatura Alta , Dose Letal Mediana , Camundongos , Microcirculação/efeitos dos fármacos , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/efeitos dos fármacos , Necrose/induzido quimicamente , Dor/induzido quimicamente , Fosfolipases A/metabolismo , Fosfolipases A2 , Pele/efeitos dos fármacos
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